Even the most ardent admirers of the Monty Python milieu (those folks who’ll fight to the death defending the relative merits of season four) will admit to longueurs between dead parrots and tinned monarchs. To these die-hard fans, we say “Behold; An animated version of Graham Chapman’s wilfully barmy demi-semi-autobiography”.

Chapman, the star of Monty Python and the Holy Grail and Life of Brian, died in 1989, but not before recording some of the mostly made-up details of his life. Openly gay and secretly alcoholic, Chapman gives an amusing account of coming out as a “raging poof” but is generally happy to pedal lies and lines from a miserable childhood: “Will you shut up about the bloody haddock!”

Three directors, most of the remaining Pythons (Eric Idle was a no-show) and 14 animation studios were involved in translating this pleasing nonsense into a 3D movie. Archival inserts allow for the Spanish Inquisition to intrude unexpectedly and a rousing blast of Sit on My Face. In an inspired piece of vocal casting, Cameron Diaz plays Sigmund Freud.

Unhappily, the results are a frightful mess. There are some neat ideas in cartoon form – the early Pythons as poo-throwing monkeys is surely apt – but too often the artwork is crudely basic or just plain weird.

Interesting details that might actually pertain to Chapman’s life are soon lost in the surreal witterings and Yellow-Pack Submarine visuals.

Suffice to say, it’s not the reunion we might have hoped for Messrs Cleese, Gilliam, Jones and Palin, and it doesn’t quite cut it as a Python primer. The season four defenders will, nonetheless, fall off their panto horses. Let’s leave them to it.